Circuit-lock



W. F. ROTERMUND.

CIRCUIT LOCK.

I APPLICATION mm FEB. 11. I919.

Patntod May 4, 1920.

UNITED STATES PATENT OFFICE.

WILLIAM F. ROTERMUND, OF SEATTLE, WASHINGTON.

CIRCUIT-LOCK.-

Application filed February 17, 1919.

To all whom it may concern:

Be it known that I, WILLIAM F. Ro'rnn sumo, citizen of the United States, residing at Seattle, in the county of King and State of lVashington, have invented certain new and useful Improvements in Circu1t Locks, of which the following is a specification.

This invention relates to an improvement in looking and controlling means for ignition circuits of internal combustion engines, in the use of which an unauthorized attempt to start the engine through closing the usual ignition switch will sound an alarm.

' The invention broadly provides an alarm means in the ignition circuit, and a shunt circuit around such alarm and of less'internal resistance than such alarm. A manually controlled, preferably key locked switch is arranged in the shunt, which switch, when closed, as in authorized use, will shunt out the alarm means, the locking of the shunt switch open, however, opens the shunt circuit and leaves only the alarm means in the circuit, to thereby sound the same if the ignition circuit is closed.

In the drawings z- Eigure 1 is a view in plan, and partly diagrammatic, illustrating the invention.

Fig. 2 is a side elevation of the improved locking and controlling means.

As here shown, 1 and 2 represent the usual lines of the ignition or starting system, and 3, the usual switch therefor, whereby said circuit may be opened and closed. The numeral 8 designates a starting motor connected in the circuit, which may be employed to crank the engine, upon closing the switch 3.

In the preferred embodiment of the present invention, the controlling and locking means comprises a casing 4:, of appropriate form, adapted, preferably to be secured on the dash of the vehicle.

An alarm means is arranged within the casing, such means being here shown as an ordinary buzzer 5, the clapper 6 of which cooperates with a gong 7 for alarm purposes. lhe ignition circuit wires 1 and 2 are led directly to and connected with the terminals of the buzzer circuit, as at S and 9, so that the buzzer is at all times mechanically in the ignition circuit. The terminal 9, is insulated from the frame and connected directly to one end of the coils, while terminal 8, is connected to the other end of the coils through the frame.

Specification of Letters Patent.

Patented May at, 1920.

Serial No. 277,483.

A. shunt circuit including wires 10 and 11, is however, connected to the ignition circuit wires, and around the buzzer, the connection being conveniently made at the buzzer terminals 8 and 9. The shunt circuit is of less internal resistance than the buzzer, and provides a path for the current which will shunt out the buzzer so long as the shunt circuit is unbroken. A look 12 of ordinary construction, having a key governed bolt 13 is mounted at one end of the casing a, and one shunt circuit wire, as 10, is connected to the lock. The belt is recessed at 1 1 and a contact strip 15 is mounted in the casing and forms the terminal of the other shunt circuit wire 11. The contact strip is so positioned that when the bolt is projected from the look, by the action of the key 16, the free end of the strip overlies the recess 14 in the bolt, and is wholly free of contact therewith. The shunt circuit is thus open. The bolt may be moved so that one edge of recess 14, will contact with strip 15, thus forming an electrical contact to close the shunt circuit, shown in dotted lines in:

Fig. 1.

When it is desired to protect the car against unauthorized use,'the lock is operated to project the bolt and open the shunt circuit. Then attempt to use the car by closing the ignition switch 8, actuates the buzzer and sounds the alarm. The authorized user of the car by moving the bolt to close the shunt circuit, establishes a path for the ignition current of less resistance than that of the buzzer, and hence the alarm will not be sounded on closing the ignition switch 3.

Claim:

A device of the character described, comprising a lock including a stationary casing and a reciprocatory bolt having electrical connection therewith, said bolt being provided in one longitudinal edge with a recess formed therein, a stationary contact bar having one end thereof permanently arranged within the recess, said recess having a substantially greater width than the contact bar so that the bolt may break electrical contact therewith when in one position, said bolt electrically contacting with the contact bar when shifted to the active position, and a circuit having one end. thereof electrically connected with the casing and its opposite end with the contact bar.

In testimonv whereof I affix my signature.

WILLIAM F. ROTERMUND. 

